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SUMMARY: As a plant‐specific transcription factor, lateral organ boundaries domain (LBD) protein was reported to regulate plant growth and stress response, but the functional research of subfamily II genes is limited. SlMYC2, a master regulator of Jasmonic acid response, has been found to exhibit high expression levels in fruit and has been implicated in the regulation of fruit ripening and resistance to Botrytis. However, its role in fruit expansion remains unknown. In this study, we present evidence that a subfamily II member of LBD, namely SlLBD40, collaborates with SlMYC2 in the regulation of fruit expansion. Overexpression of SlLBD40 significantly promoted fruit growth by promoting mesocarp cell expansion, while knockout of SlLBD40 showed the opposite result. Similarly, SlMYC2 knockout resulted in a significant decrease in cell expansion within the fruit. Genetic analysis indicated that SlLBD40‐mediated cell expansion depends on the expression of SlMYC2. SlLBD40 bound to the promoter of SlEXPA5, an expansin gene, but did not activate its expression directly. While, the co‐expression of SlMYC2 and SlLBD40 significantly stimulated the activation of SlEXPA5, leading to an increase in fruit size. SlLBD40 interacted with SlMYC2 and enhanced the stability and abundance of SlMYC2. Furthermore, SlMYC2 directly targeted and activated the expression of SlLBD40, which is essential for SlLBD40‐mediated fruit expansion. In summary, our research elucidates the role of the interaction between SlLBD40 and SlMYC2 in promoting cell expansion in tomato fruits, thus providing novel insights into the molecular genetics underlying fruit growth. [ABSTRACT FROM AUTHOR]

Abstract: Eyes absent 2 (Eya2) is a transcription factor involved in a number of cellular and developmental processes. We have previously shown that Eya2 is up-regulated during regression of cardiac hypertrophy and blocks phenylephrine-induced development of cardiomyocyte hypertrophy in vitro, suggesting that Eya2 is a negative regulator of cardiac hypertrophy. In this study, we generated transgenic mice with cardiac-specific overexpression of Eya2 to elucidate the in vivo function of Eya2 in cardiac remodeling. Mild cardiac hypertrophy developed in Eya2 transgenic mice under baseline conditions with no obvious structural or functional defects. Eya2 overexpression inhibited development of cardiac hypertrophy as judged by the abrogation of increases in heart weight and cross-sectional cell surface areas and re-activation of fetal genes under pressure overload (4 weeks). Eya2 overexpression also prevented wall thinning, ventricular dilation, and deterioration of cardiac function as well as fibrosis and inflammation in the heart under long-term pressure overload (12 weeks). Gene expression profiling using the parametric analysis of gene set enrichment (PAGE) method revealed that gene sets related to mitochondrial biogenesis and metabolism were elevated in the Eya2 transgenic mice. We also observed that the PI3K/Akt/mTOR signaling cascade was preserved in the Eya2 transgenic mice, while it was significantly reduced in the wild type littermates under pressure overload. These results demonstrate that Eya2 prevents adverse cardiac remodeling under pressure overload partly through altering metabolic gene expression and preserving PI3K/Akt/mTOR signaling pathway. [Copyright &y& Elsevier]

Key message : Over-expression of SlJA2 decreased the accumulation of SA, which resulted in significant physiological and gene expression changes in transgenic tobacco plants, leading to the decreased heat tolerance of transgenic tobacco. Abstract: NAC family, the largest transcription factors in plants, responses to different environmental stimuli. Here, we isolated a typical NAC transcription factor ( SlJA2) from tomato and got transgenic tobacco with SlJA2 over-expression. Expression of SlJA2 was induced by heat stress (42 °C), chilling stress (4 °C), drought stress, osmotic stress, abscisic acid, and salicylic acid. Over-expression of SlJA2 decreased the accumulation of salicylic acid by regulating expression of salicylic acid degradation gene under heat stress. Compared to WT plants, stomatal apertures and water loss increased in transgenic plants, and the damage of photosynthetic apparatus and chlorophyll breakdown were more serious in transgenic plants under heat stress. Meanwhile, more HO and O were accumulated transgenic plants and proline synthesis was restricted, which resulted in more serious oxidative damage compared to WT. qRT-PCR analysis showed that over-expression of SlJA2 could down-regulate genes involved in reactive oxygen species scavenging, proline biosynthesis, and response to heat stress. All the above results indicated that SlJA2 may be a negative regulator responded to plant's heat tolerance. Thus, this study provides new insight into roles of NAC family member in plant response to abiotic stress. [ABSTRACT FROM AUTHOR]

Cucumber (Cucumis sativus L.) is a high water-demanding and drought-susceptible vegetable crop. Basic leucine zipper (bZIP) transcription factors (TFs) have been linked to drought stress response in plants. Here we characterized a G subfamily gene in cucumber, CsbZIP50 , which was strongly induced by drought stress and an exogenous abscisic acid (ABA) treatment. Under drought stress, CsbZIP50 -overexpressing plants exhibited enhanced drought tolerance compared with wild-type plants, as indicated by the higher antioxidant enzyme activities but lower reactive oxygen species (ROS) and malondialdehyde contents. In addition, overexpression of CsbZIP50 enhanced cucumber's sensitivity to exogenously applied ABA, and up-regulated the expression of its stress-related genes. Moreover, we found that CsbZIP50 activated CsRD29 expression by directly binding to the G-box/ABRE cis-acting element in its promoter, both in vitro and in vivo. Yeast two-hybrid, luciferase complementation imaging, and pull-down assays showed that CsbZIP50 physically interacted with two IQ domain-containing proteins, CsIQD1 and CsIQD4, both of which promoted the ability of CsbZIP50 to activate the expression of CsRD29. Taken together, our results show that CsbZIP50 enhances drought stress tolerance in cucumber by regulating drought-responsive gene expression and ROS levels. • CsbZIP50 is a G subfamily of the bZIP TF, which was induced by drought stress and exogenous ABA treatment. • Expression of CsbZIP50 positively regulates drought tolerance by improving stomata closure and ROS scavenging. • CsbZIP50 targeted CsRD29A and the expression activation effect was enhanced by interacting with CsIQD1 and CsIQD4. [ABSTRACT FROM AUTHOR]